Various optical networks have been previously proposed for transmitting information including but not limited to audio, video and data from one location to another. Originally, the fiber optic industry used single wavelength transmission links. Multiplexing based on wavelength has been utilized more and more in optical networks to greatly increase transmission capacity over single wavelength transmission links. Specifically, wavelength division multiplexing (WDM) was developed to transmit two optical signals each having a distinct wavelength on a single waveguide. In response to the ever increasing demand, coarse wavelength division multiplexing (CWDM) was developed to further increase the transmission capacity of optical networks. CWDM allows generally up to eight different channels to be stacked in the 1550 nm range of the fiber called the C-Band. CWDM uses spacing of 20 nm. To accommodate even greater transmission capacity demands, dense wavelength division multiplexing (DWDM) has been developed to send a large number of closely spaced optical signals over a single fiber. DWDM systems have channels spaced as close as 0.4 mm.
Several companies have developed component or network products with reconfigurable add/drop multiplexers to permit remote reconfiguration of the wavelength division multiplexers to eliminate or reduce the requirement of a site visit to the node to alter or replace a fixed add/drop multiplexer to achieve the desired modification of the network. Examples of these reconfigurable add/drop multiplexers are the JDS waveblocker, the Corning waveblocker and the Photouris V32000.
Further, various protection systems have been employed in prior optical networks including channel optical dedicated protection ring (CH ODPR), multiplex section optical shared protection ring (MS OSPR) and channel optical shared protection ring (CH OSPR) to prevent transmission interruption in the event of a failure in a span of fiber or other network component.
It has not been previously known to use a reconfigurable add/drop multiplexer in an optical network having shared protection. Accordingly, previously known networks have been limited in various aspects.